Module: ColorContrastCalc::ThresholdFinder::Brightness

Extended by:
FinderUtils
Defined in:
lib/color_contrast_calc/threshold_finder.rb

Overview

Module that implements the main logic of the instance method Color#find_brightness_threshold().

Class Method Summary collapse

Class Method Details

.find(fixed_rgb, other_rgb, level = Checker::Level::AA) ⇒ Array<Integer>

Try to find a color who has a satisfying contrast ratio.

The color returned by this method will be created by changing the brightness of other_rgb. Even when a color that satisfies the specified level is not found, the method returns a new color anyway.

Parameters:

  • fixed_rgb (Array<Integer>) —

    RGB value which remains unchanged

  • other_rgb (Array<Integer>) —

    RGB value before the adjustment of brightness

  • level (String) (defaults to: Checker::Level::AA) —

    “A”, “AA” or “AAA”

Returns:

  • (Array<Integer>) —

    RGB value of a new color whose brightness is adjusted from that of other_rgb



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# File 'lib/color_contrast_calc/threshold_finder.rb', line 169

def self.find(fixed_rgb, other_rgb, level = Checker::Level::AA)
  criteria = Criteria.define(level, fixed_rgb, other_rgb)
  w = calc_upper_ratio_limit(other_rgb) / 2.0

  upper_rgb = upper_limit_rgb(criteria, other_rgb, w * 2)
  return upper_rgb if upper_rgb

  last_r, passing_r = find_ratio(other_rgb, criteria, w, w).map do |ratio|
    criteria.round(ratio) if ratio
  end

  rgb_with_better_ratio(other_rgb, criteria, last_r, passing_r)
end